The objective of this project is to determine whether UroPhos-K would be useful in the treatment of bone disease in patients with hypercalciuric idiopathic osteoporosis. The hypotheses to be tested are that hypercalciuric idiopathic osteoporosis may be caused by calcitriol excess or sensitivity, and that UroPhos-K would lower serum 1,25 vitamin D, reduce urinary calcium, inhibit bone resorption and stimulate bone formation.